Display screen or portion thereof with a graphical user interface input selector



FIG. 1 is a view of a first embodiment of a graphical user interface for a display screen or a portion thereof; and,

FIG. 2 is a view of a second embodiment of a graphical user interface for a display screen or a portion thereof.

The broken lines showing a display screen or portion thereof and elements of the graphical user interface illustrate portions of the article and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface input selector, as shown and described. 